The present invention relates to a protector for a liquid drug administration needle used for percutaneous infusion of a liquid drug into an implantable catheter which comprises an infusion catheter attached to a reservoir and is suitable for administration of a liquid drug to a patient over a long period of time.
When a liquid drug has to be administered over a long period of time, it is general practice to use a so-called implantable catheter, which is basically comprised of a reservoir to be implanted just under the skin at an appropriate site in a patient""s body, and an infusion catheter attached to the reservoir for introducing the liquid drug contained in the reservoir into a selected administration site in a patient""s body. The reservoir is provided with a septum of an elastic material, which is capable of being pierced by a cannula of a liquid drug administration needle and of sealing itself when the cannula is taken out thereform. The implantable catheter is implanted in the body so that the septum is situated just under the skin and approximately parallels to the skin surface. Thus, when introducing a liquid drug into the reservoir, it is sufficient to insert the cannula of the liquid drug administration needle connected to a drug container or the like into the reservoir through the patient""s skin and the septum.
The liquid drug administration needle which introduces the liquid drug into the implantable catheter is bent at an angle of 90 degrees to its longitudinal axis to make it convenient for needle penetration to the septum located parallel to the skin surface, i.e., to assure a correct penetration of the cannula at right angles to the skin. The liquid drug administration needles with a 90 degree-bend, made by bending a cannula protruded from a distal end of a needle hub, provide easier use as compared to the straight needles when applied to the implanted catheter, but it is troublesome to insert the cannula in the septum since the piercing position of the cannula is out of alignment with the needle grasp. Further, since the piercing position of the cannula is out of the fixed position of the hub, when the patient moves, deviation can occur between the hub and the reservoir. This causes fluctuations of the puncture depth of the cannula, resulting in increase of the risk of infection at the penetration site of the cannula. Further, with the liquid drug administration needles of the prior art, it is difficult to avoid accidental pricking of user""s finger with a needle when a physician intends to attach a protector on the liquid drug administration needle used for any patient, or to throw out the used liquid drug administration needle.
To solve such problems, a drug administration needle unit has been proposed that comprises a tabular base 120, a raised boss 160 provided on the central part of the base 120, a needle or cannula 140 bent at an angle of 90 degrees in the middle portion of the boss 160 and projected from the base 120, a handle 420 which facilitates inserting needle 140 into and withdrawing it from the patient, and a rigid protective cover 380 for protecting needle 140 (U.S. Pat. No. 4,743,231). In this needle unit, however, a pad 240 is used for holding the unit on the skin of the patient when the needle unit is inserted in the patient, so that it causes increase in production cost as compared with the conventional winged drug administration needles. In addition, the needle unit becomes large in size as a whole and takes a lot of trouble with attachment or displacement of the protective cover 380 since the protective cover 380 is so designed as to be attached to the base 120 to enclose the needle 140 and the pad 240.
It is therefore an object of the present invention to provide a protector for a liquid drug administration needle, which is relatively compact and advantageous cost and makes it possible to prevent accidental pricking of user""s finger with the needle, which may occur when applying it to an implantable catheter or discarding the used needle.
According to the present invention, the above object is achieved by employing a cannula bent at an angle of 90 egrees in the central portion of a winged hub like as the drug infusion needle of U.S. Pat. No. 4,743,231, aligning the axis of the cannula and an axis of a force applied to the hub by fingers when fitting on or taking out from the protector, and providing means for fixing the winged hub on the protector.
According to the present invention, there is provided a protector for housing a cannula of a drug administration needle, said needle comprising a winged hub and a cannula bent substantially perpendicular to an longitudinal axis of the hub at a longitudinal central portion of the hub, said protector comprising:
a tubular cannula-protecting portion having a cannula entrance at one end and a bottom at the opposite end; and
a hub-mounting portion for attachment of said winged hub, said hub-mounting portion being coaxially formed on the cannula entrance of the cannula-protecting portion.
The hub-mounting portion may be formed directly on the edge of the cannula entrance or on a flange, which has been provided on the cannula entrance to ensure prevention of the accidental pricking with the needle. The hub-mounting portion may comprise a pair of arch-shaped members with hub-engaging means on its inner wall, so that the winged hub for drug administration needle is clamped between said arch-shaped members. The cannula-protecting portion may be provided on an outside thereof with a covering portion to cover the cannula deviated from the cannula entrance.
Further scope of applicability of the present invention will become apparent form the detailed description given hereinafter. However, it should be understood that the detailed description and specific example, while indicating preferred embodiments of the invention, are given by way of illustration only; since various changes and modifications within the spirit an scope of the invention will become apparent to those skilled in he art form the detailed description.